module 3 - 7.2 mammalian gaseous exchange system Flashcards
what do all organisms require?
nutrients
the ability to excrete waste
how do many simple organisms exchange substances?
directly across their external surfaces
why do large organisms require specialised gas exchange and transport systems?
to transport substances (oxygen, nutrients) to their cells efficiently
how do fish exchange substances?
across their gills
how do insects exchange substances?
openings on their surfaces called SPIRACLES
where does gas exchange occur in mammals?
lungs and a part of the alveoli
why are all inner exchange surfaces moist?
because O2 (& some CO2) needs to be changes into aqueous solutions and needs O2to get into cells
why do land animals face a constant battle between ventilation, gas exchange, and retaining water?
- gas exchange surfaces are moist to aid diffusion by oxygen dissolving in water
- ventilation causes this water to readily evaporate
what is breathing? (in terms of ventilation)
ventilation of the lungs
how are the lungs and ribcage stuck together?
outside surface of lungs stuck to inside membrane of ribcage
what is the pleural membrane?
the double membrane that the lungs are enclosed in
what is the pleural cavity?
the space between 2 membranes and is filled with small amount of pleural fluid
what does the pleural fluid do?
- lubricates the lungs
- adheres to outer walls of the lungs to thoracic cavity by water cohesion
how is the pleural fluid connected to the membrane
hydrogen bonding
what are three important functions of the nasal cavity?
- large SA and good blood supply
- hairy lining
- moist surfaces
why is a large SA and good blood supply, an important functions of the nasal cavity?
warms the air as it passes into the body